Kinda like investing in electronic stocks that the easiest way to obtain is to whore out your machine's hardware. Currently infested with hardcore nerds with several $1000+ machines and 15 year olds with inadequate hardware hardware getting .00000014BTC/day and being excited about it
The most well known are Bitcoin, LiteCoin and Feathercoin.

Nerd 1 : "Did you see the way that cryptocoins have raised in value over the last couple of days?"
Nerd 2 : "I know, it's gone up $400 in 3 days!"
Average Computer Literate Person : "What the hell are you talking about?"